Scuttle shake

Scuttle shake is a phenomenon whereby a car - particularly an open-topped car, and particularly an open-topped car that has been created from saloon underpinnings - wobbles and shakes when going over bumps. This is due to a lack of torsional rigidity in the car's structure. It is a Bad Thing - apart from the noise and vibrations, it leads to metal fatigue and causes the car to handle unpredictably.

Manufacturers can combat scuttle shake by reinforcing the car's chassis. This makes the car more expensive than it would be otherwise, and the increased mass of reinforcement usually obliterates any weight saved by the lack of a roof.